You can have a sneak preview by looking at the current draft of pre-fascicle 5a (52 pages), last updated 18 January 2017. As usual, rewards will be given to whoever is first to find and report errors or to make valuable suggestions. I'm particularly interested in receiving feedback about the exercises (of which there are 125) and their answers (of which there are 125).
Over the years Knuth gave out over $20,000 in rewards, though most people didn't cash his highly-coveted "hexadecimal checks", and in 2008 Knuth switched to honorary "hexadecimal certificates". In 2014 Knuth complained about the "dumbing down" of computer science history, and his standards remain high. In his most-recent update, 79-year-old Knuth reminds readers that "There's stuff in here that isn't in Wikipedia yet!"